Xanda

This past weekend I was helping a friend do his brakes. The fronts went smooth from start to finish and the rear went well until we tried to put the new pads into the caliper.

We could freely drop in the pads but when we tried to re-insert the pin it wouldn't go through the first hole in the caliper and the hole on the inboard pad nicely.

I tired cleaning the inside of the caliper to see if debris in there was stopping the pad from getting inserted all the way and it didn't help. Basically it seemed like the pad was a tad too tall and thus the holes wouldn't align properly.
What makes this even more interesting is that when I compared the old and new pad outside of the caliper they seemed to match in their dimensions.
In the end we put the old pads in because they still had some meat left on them. The fronts were the ones that really needed a replacement and we just decided to include the rear anyway since it had been a while since they were replaced.

Is there a trick to getting new pads into the caliper for the rear? I was tempted to try tapping the pin in with a hammer but didn't want to force anything.

Norwichdelta06

did you push the pistons back? Reinsert your PADS. Take off the cap off the brake resorvioir. And use a flathead and push against the old pads not the rotor to give yourself room

Glyn M Ruck

As I said in your other thread - crack open the bleed screws to push the pistons back or you can damage the ABS unit.

Norwichdelta06

True.. but you can just take off the brake fluid cover and youll be fine

Xanda

The pistons were pushed back in safely with no problems.
There's no problem with the amount of space between the new rotor and the piston at all, it's like the pad is too tall or the slight bulges on the side of the pad are a little wider than spec.

Glyn M Ruck

Not so. Taking off the fluid reservior cover & watching level prevents an overflow but does not prevent undesireable back pressure on the shunt/accumulator valves in the ABS block when pushing caliper pistons back. We have recently seen a number of ABS block failures in SA due to techs pushing back pistons too hard without cracking bleed screws. This is a very expensive repair for being careless. splinter has always advocated cracking open bleed screws & has been proven correct.

If the calipers are clean of all pad debris build up - Go buy a new set of genuine MB pads & quote your VIN. Sounds like wrong or badly made pad backplates.

Norwichdelta06

you nkow what glyne your on to something! Maybe you just got the wrong rear pads? MAybe sport and non sport got mixed up? Can easily happen? What company did you get

eesjunin

he said he compared them side to side and they were identical

Xanda

NPN pads.
And yes they looked identical. I might pull the used pads and see if there are any nuances that I may have missed.